Dunno if this is any help but got my ipod touch 5th gen today and was messing around in my JCW with the media system, as I haven't bought the Y-lead (lightning) version yet but wanted audio.

Tried using a 3.5mm to 3.5mm jack and the USB > lightning lead that came with the ipod, plugged into the underdash connectors. Looks like it works as well as the y-lead. Can control via MFSW, select playlists, track info displayed on Nav screen. Bit messy but seems to work fine